Question

Given below are two statements:
Statement (I) : Fusion of MnO$_2$ with KOH and an oxidising agent gives dark green K$_2$MnO$_4$.
Statement (II) : Manganate ion on electrolytic oxidation in alkaline medium gives permanganate ion.
In the light of the above statements, choose the correct answer from the options given below.

• A. Both Statement I and Statement II is true
• B. Both Statement I and Statement II is false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Answer 1

The Correct Option is A

The prompt presents two assertions concerning the chemistry of manganese compounds and requires their validity assessment through chemical principles and reactions.

Statement I: The fusion of \(MnO_2\) with \(KOH\) and an oxidizing agent yields the dark green compound \(K_2MnO_4\).

Explanation: When manganese dioxide (\(MnO_2\)) is heated with potassium hydroxide (\(KOH\)) in the presence of an oxidizing agent like chlorine (\(Cl_2\)) or potassium nitrate (\(KNO_3\)), potassium manganate (\(K_2MnO_4\)), which is dark green, is formed.

The reaction is: \(2MnO_2 + 4KOH + O_2 \rightarrow 2K_2MnO_4 + 2H_2O\)

Consequently, Statement I is confirmed as true.

Statement II: Electrolytic oxidation of the manganate ion in an alkaline medium produces the permanganate ion.

Explanation: Within an alkaline environment, the manganate ion (\(MnO_4^{2-}\)) can undergo further oxidation to yield the permanganate ion (\(MnO_4^{-}\)), particularly under electrolytic conditions. This transformation results from the \(MnO_4^{2-}\) ion gaining an electron:

\(MnO_4^{2-} \ + \ e^- + \ H_2O \rightarrow \ MnO_4^- + 2OH^-\)

This indicates an increase in the oxidation state of manganese from +6 in manganate to +7 in permanganate.

Therefore, Statement II is also established as true.

Conclusion: Both Statement I and Statement II are validated by the provided explanations. The correct determination is: Both Statement I and Statement II is true.